The virus is spread by mosquitoes, which are expected to be in large number following recent rainfall events and pending hot days.
Japanese encephalitis is a rare but serious illness, with the most serious cases causing lifelong neurological complications or even death.
NSW Health is encouraging people to protect themselves by getting the vaccine.
It is considered safe and effective for people aged two months and older, and is recommended for those at the highest risk of catching Japanese encephalitis.
Some sections of the community can access the vaccine for free.
You must live in an area of high JEV concern and:
• regularly spend time outdoors placing them at risk of mosquito bites; or
• are experiencing homelessness; or
• are living in conditions with limited mosquito protection (e.g. tents, caravans, dwellings with no insect screens); or
• are engaging in outdoor flood recovery (clean-up) efforts, including repeated professional or volunteer deployments.
Before the 2021-2022 mosquito season, Japanese encephalitis virus had rarely been found in Australia with previous cases noted only in Northern Australia, Cape York and the Torres Strait.
It is not known how Japanese encephalitis virus came into mainland Australia, but the movement of infected mosquitoes or migratory water birds may have played a part in the virus' spread, combined with significant rain events.
Japanese encephalitis virus has now been detected in pigs and humans in Western and Southern NSW, as well as in Queensland, Victoria, the Northern Territory and South Australia.
Most people who get Japanese encephalitis do not have any symptoms, but common symptoms do include fever, headache and vomiting.
People with a severe infection (1 in every 250 people) may get symptoms such as neck stiffness, disorientation, tremors, seizures and paralysis, or may go into a coma.
If you get these symptoms, contact a doctor right away, or Healthdirect on 1800 022 222.
In an emergency, call Triple Zero (000) or visit your nearest emergency department.
